A National survey on substance use among Iranian industrial workers.

Background: Recent evidence shows that the prevalence of substance abuse is 2.1% in Iranians aged 15-64 years, while reported rates are higher in studies that target industrial workplaces. Our study intends to provide a national picture of substance use among industrial workers in Iran. Methods: This survey was designed to collect data through interviews and dipstick urine tests. Using a multi-stage sampling approach, we recruited our study subjects from a representative sample of industrial workers from all provinces in 2015. Data were weighted to estimate the prevalence rate of substance use. Odds ratios were calculated through adapting logistic regression to test the strength of association between substance use (based on self-report and urine test) and sociodemographic factors including sex, age group, education level, marital status and worker's professional training status. All statistical analyses were conducted using SPSS Version 22. P <0.05 was considered significant. Results: We analyzed the data collected from 13,128 participants; both self-reported use and urine test results. Majority of the respondents were male (n=12077, 92%), aged 21-40 years old (n=9491, 72.3%), had finished middle/secondary school (n=8353, 63.6%) and were married (n=11012, 83.9%). Opium was the most popular abused substance (n=352, 2.7%) followed by alcohol (304, 2.3%), based on self-reports. Urine tests showed that 23.8% (n=3105) of the participants had a positive result for the use of opiates/opioids, crystal meth and/or cannabis. The highest rate of substance use reported from a province was 60.50%; the lowest provincial rate was 9.0%. Conclusion: Nearly a one-fourth of Iranian industrial employees are engaged in use of substances with significant geographical distribution. Urine test is the recommended method to assess the prevalence of drug use among industrial workers in Iran.